Gas giant

A gas giant is a huge planet made entirely of base gases, including fluorine, methane, and ammonia. Typically they do not possess a solid surface, but rather have dense atmospheres. These turbulent atmospheres are generally made of the same materials as stars, however, they lack the mass necessary to begin nuclear fusion. Theoretically, if two gas giants collide, they may be able to create a self-sustaining fusion reaction, leading to the birth of a new star. (TNG: "Ship in a Bottle")

Neelix's cousin once had a job transporting disulfides from a gas giant. He enjoyed the turbulence, according to Neelix, who also noted that "disulfides are known to cause delusions." (VOY: "Friendship One")